HP StorageWorks External Storage XP user guide (T1706-96006, June 2006)

External Storage XP user guide 37
concern, ensure that the external LU’s Path Blockade Watch time is the same as or shorter than the host
command’s timeout period.
• Host access to the external storage LU must be via the local array, and must not be via a direct physical
connection to the external storage device LU. For external array LUs not involved with External Storage
XP, direct access from a host is allowed for all supported external storage except MSA. If you use MSA
as external storage, it must be entirely dedicate as external storage.
• For all external storage, either set the ES XP cache mode option in Command View XP or XP Remote
Web Console to cache disabled or partition resources associated with external storage in its own CLPR
(for example, CLPR1). While HP strongly recommends this new default for all external storage in
general, this new default is mandatory for any external array that is slower than an XP12000 external
port (for example, the Modular Smart Array product line) unless it resides in its own CLPR partition with
isolated port/MP/cache resources.
Combining External Storage XP with other HP StorageWorks products
You can use HP StorageWorks software products to operate and manage the external LUs you set using
External Storage XP.
The following sections provide configuration examples for specific HP StorageWorks software products:
• ”Using external LUs for Auto LUN XP operations” on page 39
• ”Using external LUs for Continuous Access XP operations” on page 39
• ”Using external LUs for Continuous Access XP Journal operations” on page 40
• ”Using external LUs for Business Copy XP operations” on page 41
• ”Using external LUs for Snapshot XP operations” on page 42
The following HP StorageWorks software products support the use of mapped external LUs. For operations
and notes about each software product, see the product’s user guide.
• LUN Manager
• If you set an open-system emulation type when mapping the external LU, you must use LUN
Manager to set the mapped LU’s path.
• You cannot use the mapped external LU as a NAS system volume.
• You cannot use the mapped external LU as a NAS user volume.
• Volume Manager
• If you set a mainframe-system emulation type when mapping the external LU, you must format the
mapped volume or perform the Write to Control Blocks operation using the Custom Volume Size
(CVS) function before putting the external LU into use. For instructions, see the HP StorageWorks
LUN Configuration and Security Manager XP user guide for the XP12000/XP10000/SVS200.
• If you use the CVS function to create LDEVs from an external XP LU, the created LDEVs’ attributes (IO
Suppression mode and Cache Mode) are the same as the source external LU’s.
• You cannot combine the local array internal LDEV and external LU to form a LUSE volume.
• Do not combine LDEVs of multiple external LUs to create a LUSE volume. You can only use LDEVs in
the same external LU to set LUSE volumes.
• You cannot combine external LUs that have different IO Suppression modes to form a LUSE volume.
• You cannot combine external LUs that have different Cache Mode settings to form a LUSE volume.
• Cache LUN XP
• You must set the IO Suppression mode to Disable to use the mapped external LU for Cache LUN XP
operations.
• You cannot specify Cache LUN XP’s bind mode for an external LU that has Cache Mode set to
Disable.
• If you use the mapped external LU for a Cache LUN XP operation and set the bind mode, the Cache
LUN XP operation requires a cache that is twice the size of the user data.
• Continuous Access XP (Synchronous and Asynchronous)